最基本的增删查改语句
建表
create databases qq;
create table usertest(
qid int primary key,
name varchar(50),
age int );
插入语句
insert into usertest values(1,’张三’,20);
部分插入insert into usertest (id,name) values(2,’李四’);
删除语句
delete from usertest;
条件删除
delete from usertest where qid = ‘1’;
更新语句
update usertest set age =22, where qid = 2;
查询语句(内容相对较多,可能会跟在下一贴)
再新建一张表
create table number(
qno int primary key,
qname nchar(30),
qid int foreign key references qq(qid)
)
select * from number;(尽量不用)
select qname from number where 条件;
select distinct qid from number;–去重复,只能单一,不能去重两个字段
select qname qq名称 from number; –(qq名称是别名)
select qname from number where qid like ‘__3%’;– 查询第三个数为3的qid的qname。
select qname from number where qid like’3%’; –查询带有3的qid的qname。